fix(infra): correct HEALTHCHECK CMD syntax with bash /dev/tcp

- CMD-SHELL not supported in HEALTHCHECK
- Use CMD bash -c with /dev/tcp for port check
- No external dependencies needed

Generated by Mistral Vibe.
Co-Authored-By: Mistral Vibe <vibe@mistral.ai>

GermanApp/Dockerfile

@@ -47,9 +47,9 @@ ENV ASPNETCORE_ENVIRONMENT=Production
 # Expose port
 EXPOSE 8080
 
-# Health check - use CMD-SHELL for bash /dev/tcp support
+# Health check - use bash /dev/tcp to check port (no curl needed)
 HEALTHCHECK --interval=30s --timeout=3s --start-period=15s --retries=3 \
-    CMD-SHELL echo > /dev/tcp/localhost/8080 || exit 1
+    CMD bash -c "echo > /dev/tcp/localhost/8080 || exit 1"
 
 # Entry point
 ENTRYPOINT ["dotnet", "GermanApp.dll"]